Field of the Invention
The invention relates to a targeting device for guiding a drill arrangement for forming an arc-shaped bore in an assembly of adjacent bones or bone fragments, respectively.
Description of Related Art
From document WO 2011/072249 A1, a guidewire targeting device for assisting in the arthrodesis of the heel is known that allows the formation of two straight cutting paths starting from a bottom section of the calcaneus and extending through the talus towards the tibia canal using guide wires, which are angled relative to each other. Using a drill and a reamer after removing the targeting device, a bent bore or canal may be established from a combination of paths that may receive an immobilizing nail. Tubular sleeves are used in the targeting device to guide the wires straight through the bone material.
This approach, however, suffers from an increased damage of bone material as two cutting paths are created. Further, the patient may suffer from pain when the bottom portion of the calcaneus is involved in the surgical process. Moreover, duration and stability of the overall configuration may not be satisfactory. Therefore, in some surgical applications, a further need for forming bores in bone material departing from the commonly applied straight shape has arisen in the recent past.
Some of those applications relate to drilling arc-shaped bores into a bone or an assembly of multiple adjacent bones.
A device for forming an arcuate channel in vertebrae has, for example, been proposed in US 2005/0267481 A1, wherein two path-guard members connected with each other via a platform assembly are attached to each one vertebra by multiple nails, respectively. A pivot arm mounted at the platform holds an arc-shaped tube member through which a drive cable extends that is driven by a motor such as to rotate a drill bit arranged at a front end of the tube member. Due to the arcuate shape of the tube an arc-shaped bore hole can be drilled when the pivot arm is advanced towards the bone. In this manner, an intervertebral disk can be directly accessed through the arc-shaped bore that is cut into adjacent vertebral bodies and through respective end faces thereof.
Another device for forming a bore in an arcuate shape is described in US 2010/0292722 A1. The device comprises a main body attached to the heel of the human body by means of Kirschner-wires, and an arc-shaped guide enables guiding a tube having a corresponding radius of curvature rc to perform a pivoting movement. The device is attached to the heel at two locations. A drill bit driven by a motor via a drive cable extending through the tube enters into the calcaneus first, and then advances the arcuate-shaped bore through the talus into the marrow space of the tibia. The circular arc-shaped bore thus formed allows inserting a corresponding nail which immobilizes the bones involved.